Hollow slide valves



Dec. 9, 1969 R. F. HoDGsoN HOLLOW SLIDE VALVES Filed March 4, 1968 2 Sheets-Sheet 1 ATTORNEYS Dec. 9, 1969 R. F. HoDGsoN 3,482,600

HOLLOW SLIDE VALVES Filed March 4, 1968 2 Sheets-Sheet 2 49 34 47 3l I4 I7 74 75 I7 58 32 60 INVENTOR ROBERT F. HODGSON ATTORNEYS 'United States Patent O 3,482,600 HOLLOW SLIDE VALVES Robert F. Hodgson, Canfield, Ohio, assignor to Commercial Shearing & Stamping Company Filed Mar. 4, 1968, Ser. No. 710,091 Int. Cl. F16k 31/44, 3/00 U.s. ci. 137-5961 s Claims ABSTRACT OF THE DISCLOSURE This invention relates to a hydraulic control valve, and particularly to the double acting type having improved replenishing flow features.

In order to avoid cavitation in the piston side of a differential area piston motor when the piston is rapidly moved, it is common to replenish the pump flow to the piston side with the exhaust flow from the rod side of the piston motor. This replenishing ow is oftentimes regulated by the control valve. Typical of such a control valve is that illustrated in the Ruhl Patent No. 3,006,372. One drawback of Ruhls valve is its complexity. Ruhl diverts replenishing fluid through internal coring in his valve body and into his open center pump flow path. I have found that I can avoid the complex coring of Ruhls valve and provides replenishing flow directly through my valve element to the piston side of the motor.

More specifically, my simplified control valve preferably includes: a valve body having a bore, a parallel flow passage, an open center inlet and outlet chambers, work port chambers adapted to be connected to the piston side and rod side, respectively, of a piston motor; a hollow spool valve slidably received in the bore and shiftable from a neutral position to either a raise or lower work position; the valve element being suitably formed to direct flow to either the rod or piston side of the piston motor when the valve element is in the raise or lower positions, respectively; and the valve element being further adapted to direct return iluid iiow from the rod side of the piston motor to the piston side thereof when the valve element is in the lower position and during rapid movement of the piston. It is emphasized that the replenishment ow is directed through the valve element to the work port chamber to which the piston side of the piston motor is connected. In this invention there is no secondary diversion of fluid to the open center chambers and then back into the hollow spool as in the case of the Ruhl valve.

Other details, objects and advantages of the invention will become apparent as the following description of a present preferred embodiment thereof proceeds.

In the accompanying drawings I have shown a present preferred embodiment of the invention in which:

FIGURE 1 is a longitudinal sectional view through a double acting hydraulic control valve embodying my invention with the valve element in a neutral position;

FIGURE 2 is a sectional view taken along the line II-II of FIGURE 1;

FIGURE 3 is a sectional view taken along the line III-III of FIGURE 1;

FIGURE 4 is a longitudinal sectional view of the valve ice of FIGURE 1 showing the valve element in a raise work position; and

FIGURE 5 is a longitudinal sectional view of the valve of FIGURE 1 showing the valve element in the lower work position.

Referring now to the drawings wherein like reference numerals refer to like parts throughout the various iigures, 10 generally designates a double acting hydraulic control valve section, including an elongated body 12 adapted to be attached with other valve body sections by nuts and bolts, for example, to form a desired multivalve arrangement. Such arrangements are well known as typified by the series-parallel-priority valve arrangement disclosed in U.S. Patent No. 3,329,169 granted July 4, 1967. Body 12 has a longitudinal bore 14 extending therethrough with a double acting sliding valve element 16 being suitably received therein. A bifurcated inlet passage 17 having chambers 18 and 19 intersecting bore 14 receives high pressure fluid from a source, not shown, through an inlet section, also not shown but well known in the art. An outlet chamber 20 intersects bore 14 between inlet chambers 18 and 19. A branch chamber 22 intersects bore 14 adjacent inlet chamber 19 and cornmunicates through passage 23 with parallel flow passage 24 lying in a plane spaced beneath and generally parallel to the plane of the inlet and outlet chambers. Parallel flow passage 24 receives high pressure fluid from the same source as that providing uid to inlet passage 17. Work ports 28 and 30 open out of body 12 and communicate with chambers 31 and 32 intersecting bore 14 on opposite sides of inlet chamber 18 and branch chamber 22, respectively. Exhaust chambers 34 and 35 intersect bore 14 on opposite sides of work chambers 31 and 32, respectively, and communicate with the respective work chambers through passages 36 and 37. Identical pressure relief valves 38 and 39 are suitably received in passages 36 and 37, respectively.

Valve element 16 is shown in FIGURE l in a neutral position and can be shifted to the raise position shown in FIGURE 4 and the lower position shown in FIGURE 5 by any well-known means, as by suitable linkages, for example connected to the right side of valve element 16, as viewed in FIGURE l. Valve element 16 is urged into its neutral position by a helical coil spring 40 urging a force on either colar 41 or 42 suitably arranged on valve element 16, with the direction of the force depending on the longitudinal position of the valve element. A hollow housing 43 suitably fixed to body 12 encloses spring 40, collar members 41 and 42, and the left side of valve element 16. Valve element 16 has a hollow chamber 45 extending longitudinally therethrough. Circumferentially spaced first openings 47 extend radially into communication with a left portion of hollow chamber 45. A plug 49 is threadedly received in the left end of valve element 16. A pressure responsive closure means in the form of a cupshaped check valve 51 closes first openings 47 from the central portion of hollow chamber 45. A helical coil spring 52 in compression is suitably disposed between the inner end of plug 49 and check valve 51 to urge same into its closed position. Check valve 51 has a plurality of Circumferentially spaced openings 54 extending radially through the inner end portion thereof and communicating with openings 47 when check valve 51 is in its closed position. A generally cylindrically shaped sleeve member 55 is suitably carried by body 12 and extends inwardly into exhaust chamber 34 and terminates in a generally vertical plane extending through an intermediate point of openings 47 when valve element 16 is in its neutral position.

Circumferentially spaced second openings 58 extend radially through valve element 16 into communication with hollow chamber 45, which second openings are disposed rightwardly of the transverse center of valve element 16. Circumferentially spaced third openings 60 are disposed rightwardly of second openings` 58 and extend radially through valve element 16 into communication with hollow portion 45. A clevis spool 62 is threadedly received in the right end of valve element 16. A pressure responsive closure means in the form of a cup-shaped check valve 64 closes third openings 60 from the central portion of hollow chamber 45. A helical coil spring 66 in compression is suitably disposed between the inner end of clevis spool 62 and check valve 64 to urge same into its closed position. The compressive force of spring 66 is greater than that of spring 52, for reasons to be specified hereinafter. Check valve 64 has a plurality of circumferentially spaced openings 68 extending radially through the inner end portion thereof and communicating with third openings 60 when check valve 64 is in its closed position.

Valve element 16 has a left land 70, right land 71, central land 72, and intermediate land 73 disposed between the central and left lands. Grooves 74 and 75 are disposed on the opposite sides of central land 72 with groove 74 being disposed rightwardly of intermediate land 73. Another groove 76 is disposed between intermediate land 73 and left land 70. With valve element 16 in its neutral position groove 76 extends leftwardly from a point adjacent inlet chamber y18 across work chamber 31 to adjacent exhaust chamber 34.

In use, the work ports 28 and 30 of valve 10 are connected with the opposite ends of a double-acting difierential area piston motor 80 by lines 82 and 84, respectively, as shown in FIGURE l. The rod end of motor 80 is illustrated as being connected to a load, typical of which can be the bucket of an earth moving vehicle. With the valve element 16 in the neutral position shown in FIG- URE 1 the open-center chambers are clear to 'bypass pump ilow downstream. That is, uid entering body 12 is free to pass through inlet chambers 18 and 19 to outlet chamber 20. Fluid will also pass freely downstream through parallel ow passage 24. Work chambers 31 and 32 are blocked by valve element 16. To raise the piston of piston motor 80 the valve element 16 is placed in the position shown in FIGURE 4. Open center is thus blocked. That is, communication between inlet chambers 18 and 19, and outlet chamber 20 is blocked. The second openings 58 are aligned with branch chamber 22 and iluid flowing through parallel ilow passage 24 'will flow through second openings 58 into hollow chamber 45 of valve element 16. Sleeve member 55 prevents the fluid from entering exhaust chamber 24 through rst openings 47 so the iiuid will urge check valve 64 rightwardly and will iiow through third openings 60 into work chamber 32 and out work port 30 into the rod side of piston motor 80. Return uid from the piston side of piston motor 80 will enter work port 28 by way of line 82 and into work chamber 31, around groove 76, into exhaust chamber 34 and back to reservoir. Check valve 64 also serves to prevent any back ow of fluid between the rod side of piston motor 80 and parallel passage 24.

FIGURE shows the valve element 16 shifted rightwardly into the lower position, In the lower position, open center is blocked. That is, communication between outlet chamber and inlet chambers 18 and 19 is blocked. With the piston motor loaded, fluid will flow from parallel flow passage 24 into branch chamber 22 around groove 75 to be combined with the uid flow in inlet chamber 19. The combined flow in inlet chamber 19 passes across groove 76 to work chamber 31, out of work port 28, and through line 82 into the piston end of piston motor 80. Pressurized uid in work chamber 31 enters behind check valve 51 through rst openings 47 and openings 54, and holds check valve 51 in the closed position. Return fluid from the rod side of piston motor 80 enters work port through line 84, and then through second openings 58 into the hollow portion 45 of valve element 16. Check valve 51 is held closed by the pressurized iluid 4 behind it, and, thus, the nid in hollow portion 45 will urge check valve 64 rightwardly and thereby flow into exhaust chamber 35 and back to reservoir.

When the piston motor is subjected to a weight which would cause the cylinder to move at such a rate that the fluid cannot fill the piston side of the piston motor, then the following sequence occurs. The pump uid flow will continue to ow into work chamber 31 from inlet chamber 18 around groove 76. The pressure in work chamber 31 will, however, drop off, as will the pressure behind check vave 51. The return ow from the rod side of piston motor 80 will enter hollow portion 45 of valve element 16. This return fluid will now urge check valve 51 leftwardly to open first openings 47 to work chamber 31. This movement of check valve 51 will result since, as noted earlier, the compression force of spring 66 acting on check valve 64 is greater than that of spring 52 acting on check valve 51. Thus, the return flow from the rod side of piston motor 80 will be diverted to work chamber 31 and then to the piston side of the piston motor 80. Accordingly, cavitation in the piston side of piston motor 80 will be avoided during the rapid movement of the piston.

The compression force of the spring 66 acting on check valve 64 can be suitably selected to determine the amount of uid to be diverted around check valve 51 during the rapid movement of the piston of piston motor 80. Alternatively, the compression force of spring 52 acting on check valve 51 could be suitably selected for the same reason.

As indicated earlier, it should be noted that replenishing fluid for supplementing fluid ow to the piston side of piston motor 80 flows directly through the hollow chamber 45 of valve element 16 to work chamber 31. There is no secondary diversion of iluid to the open center inlet chambers 18 and 19 and then back into the hollow chamber 45 of the valve element 16 as was done in the control valves heretofore used. Accordingly, the valve of the present invention is considerably simpler in construction than the previously known flow replenishing type control valves.

I claim:

1. A hydraulic control valve comprising: an elongated body having inlet and outlet means, a longitudinally extending bore therethrough, an inlet chamber intersecting said bore and communicating with said inlet means, an outlet chamber intersecting the bore spaced from the inlet chamber and communicating with the outlet chamber, a parallel ow passage extending through said body transverse to the bore and spaced therefrom, a branch chamber intersecting said bore and communicating with said parallel flow passage, a irst Work port chamber intersecting said bore and having means adapted to be connected to the piston side of a piston motor, a second work port chamber intersecting said bore and having means adapted to be connected with the rod side of a piston motor, exhaust chamber means intersecting said bore adjacent each of said work port chambers and communicating therewith, an elongated hollow, closed ended valve element slidably received in said bore, said valve element shiftable longitudinally in said bore from a neutral position in which fluid entering said inlet chamber enters said outlet chamber around a rst reduced portion of said valve element and uid entering said parallel flow passage ilow passage ows entirely downstream, said valve element being shiftable from asid neutral position to raise and lower work positions, said valve element having first, second and third openings extending radially therethrough and a second reduced portion adjacent said rst openings; rst pressure responsive closure means received in said valve element for closing said first openings; second pressure responsive closuremeans received in` said valve element for closing said third openings; said valve element having means adapted when in said raise position to block communication between said inlet and outlet chambers while connecting said branch chamber to said second openings, and saidthird openings with said second work port chamber and said first work port chamber to the exhaust chamber means adjacent thereto around said second reduced portion of said valve element, whereby fiuid fiows from said parallel ow passage to open said second closure means to flow to the rod side of the piston motor and fiuid exhausted from the piston side of the piston motor fiows through said first work port chamber around said secondireduced portion of said valve element; said valve having means further adapted when in said lower position to block communication between said inlet and outlet chambers while connecting said branch chamber with said inlet chamber around said first reduced portion, connecting said inlet chamber to said first work port chamber around said second reduced portion, connecting said second work port chamber with the exhaust means adjacent thereto through said second and third openings, and connecting said first work port chamber to said first openings, whereby fiuid will fiow from said inlet chamber to the piston side of the piston motor and fluid from the rod side of the piston motor opens said second closure means to fiow to exhaust; and said first closure means being pressure responsive to open, when said valve element is in said lower position at a pressure in said first work port chamber below a predetermined pressure such that at least a portion of the fiuid flow from the rod side of the piston motor will fiow to the piston side of the piston motor through said valve element and said second and first openings.

2. A hydraulic valve as set forth in claim 1 wherein said first closure means is a slidable first-check valve; said second closure means is a slidable second check valve; and said first check valve has a portion thereof in cornmunication with the fiuid presure in the piston side of the piston motor when said valve element is in said lower position, such that said fiuid pressure acts on said first check valve to hold same closed until said fiuid pressure drops below a predetermined value.

3. A hydraulic valve as set forth in claim 2 wherein said first check valve includes a first biasing means; said second check valve includes a second biasing means; said biasing means having relative compressive forces acting on their respective check valves for regulating the amount of fluid fow from the rod side of the piston motor to the piston side thereof when said valve element is in said lower position and the pressure in said first work port chamber drops below said predetermined pressure.

4. A hydraulic control valve comprising: an elongated body having inlet and outlet means, a longitudinally extending bore therethrough, an inlet chamber intersecting said bore and communicating with said inlet means, an outlet chamber intersecting the bore spaced from the inlet chamber and communicating with the outlet chamber, a parallel ow passage extending through said body transverse to the bore and spaced therefrom, a branch chamber intersecting said bore and communicating with said parallel ow passage, a first work port chamber intersecting said bore and having means adapted to be connected to the piston side of a piston motor, a second work port chamber intersecting said bore and having means adapted to be connected with the rod side of a piston motor, ex-

haust chamber means intersecting said bore adjacent each of said work port chambers and communicating therewith; an elongated hollow, closed ended valve element slidably received in said bore, said valve element shiftable longitudinally in said bore from a neutral position in which fiuid entering said inlet chamber enters said outlet chamber around a rst reduced portion of said valve element and fiuid entering said parallel flow passage flows entirely downstream, said valve element being shiftable from said neutral position to raise and lower work positions, said valve element having means adapted when in said raise position to block communication between said inlet and outlet chambers while connecting said branch chamber to said second work port chamber and connecting said first work port chamber to the exhaust chamber means adjacent thereto around a second reduced portion of said valve element, said valve having means further adapted when in said lower position to block communication between said inlet and outlet chambers while connecting said branch chamber with said inlet chamber around said first reduced portion, connecting said inlet chamber to said first work port chamber around said second reduced portion, connecting said second work port chamber with the exhaust means adjacent thereto; and connecting said first work port chamber to said first openings; and said valve element having means yet adapted when in said lower position to divert at least a portion of the fiuid ow from the rod side of the piston motor to=the piston side of the piston motor directly through said valve element when the pressure in said first work port chamber drop below a predetermined value.

5. A hydraulic valve as set forth in claim 4 wherein said valve element has first, second and third openings extending radially therethrough; first and second pressure responsive closure means for closing said first and third openings, respectively; said second closure means being responsive when said valve element is in said raise position to open under the fiuid pressure in said valve element such that fiuid ows to said second work port chamber from said parallel ow passage through said second and third openings; said first closure means being responsive when said valve element is in said lower position to open under the fluid pressure in said valve element, and when the pressure in said first work port chamber drops below said predetermined value such that fiuid will flow from said second work port chamber through said valve element and said first openings into said first work port chamber.

References Cited UNITED STATES PATENTS 2,965,133 12/1960 Rice et al IS7-612.1 3,006,372 10/1961 Ruhl 91-436 XR 3,390,700 7/1968 Hodgson et al 137-5962 HENRY T. KLINKSIEK, Primary Examiner U.S. Cl. X.R. 

